Introduce LanguageMode, drop StrictMode.

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_H_
 #define V8_AST_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 2448 matching lines @@
   const AstRawString* raw_name() const { return raw_name_; }
   Scope* scope() const { return scope_; }
   ZoneList<Statement*>* body() const { return body_; }
   void set_function_token_position(int pos) { function_token_position_ = pos; }
   int function_token_position() const { return function_token_position_; }
   int start_position() const;
   int end_position() const;
   int SourceSize() const { return end_position() - start_position(); }
   bool is_expression() const { return IsExpression::decode(bitfield_); }
   bool is_anonymous() const { return IsAnonymous::decode(bitfield_); }
-  StrictMode strict_mode() const;
+  LanguageMode language_mode() const;
   bool uses_super_property() const;
   bool uses_super_constructor_call() const;
 
   static bool NeedsHomeObject(Expression* literal) {
     return literal != NULL && literal->IsFunctionLiteral() &&
            literal->AsFunctionLiteral()->uses_super_property();
   }
 
   int materialized_literal_count() { return materialized_literal_count_; }
   int expected_property_count() { return expected_property_count_; }
@@ skipping 1068 matching lines @@
 
  private:
   Zone* zone_;
   AstValueFactory* ast_value_factory_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_